Alkylation of aromatic hydrocarbons



This application is a continuation-in-part of ur copending application Serial No. 722,121, filed March 18, 1958, now Patent No. 2,939,890, June 7, 1960.

This invention relates to a process for the alkylation of aromatic hydrocarbons, and more particularly relates to a process for the alkylation of aromatic hydrocarbons with olefin-acting compounds in the presence of a catalyst comprising a boron trifiuoride modified substantially anhydrous zirconium oxide. Still more particularly this invention relates to a process for the alkylation of benzene hydrocarbons with olefin-acting compounds in the presence of a catalyst comprising boron trifluoride and boron trifluoride modified substantially anhydrous zirconia.

An object of this invention is to produce alkylated aromatic hydrocarbons, and more particularly to produce alkylated benzene hydrocarbons. A specific object of this invention is to produce ethylbenzene, a desired chemical intermediate, which is utilized in large quantities in dehydrogenation processes for the manufacture of styrene, one starting material in the production of some synthetic rubbers. Another specific object of this invention is a process for the production of cumene by the reaction of benzene with propylene, which cumene product may be oxidized to form cumene hydroperoxide, which latter compound is readily decomposed into phenol and acetone. Another object of this invention is the production of paradiisopropylbenzene, which diisopropylbenzene product is oxidized to terenhthalic acid, one starting material for the production of some synthetic fibers. A further specific object of this invention is to produce alkylated aromatic hydrocarbons boiling within the gasoline boiling range having high antiknock value and which may be used as such or as components of gasoline suitable for use in automobile engines. Still another object of this invention is the alkylation of aromatic hydrocarbons with so-called refinery off-gases or dilute olefin streams, said olefincontaining streams having olefin concentrations in quantities so low that such streams have not been utilized satisfactorily as alkylating agents in existing processes without prior intermediate olefin concentration steps. This and other objects of the invention will be set forth hereinafter in detail as part of the accompanying specification.

Previously, it has been suggested that boron trifiuoride can be utilized as a catalyst for the alkylation of aromatic hydrocarbons with unsaturated hydrocarbons. For example, Hofmann and Wulif succeeded in replacing aluminum chloride by boron tritiuoride for catalysis of condensation reactions of the Friedel-Crafts type; (German Patent 513,414 and British Patent 307,802). Aromatic hydrocarbons such as benzene, toluene, tetralin, and naphthalene have been condensed with ethylene, propylene, isononylene, and cyclohexene in the presence of boron trifluoride with the production of the corresponding monoand polyalkylated aromatic hydrocarbon derivatives. In these processes rather massive amounts of boron trifluoride have been utilized as the catalyst. Similarly, the olefin utilized has been pure or substantially pure. No successful processes have yet been introduced in which the olefin content of a gas stream, which is rather dilute in olefins, has been successfully consumed to completion in the absence of some olefin concentration step or steps. By the use of the process of the present invention, such gas streams may be utilized per se as alkylating agents along tes atent O ice with minor amounts of boron trifiuoride and substantially complete conversions of the olefin content are obtained.

One embodiment of this invention relates to a process for the production of an alkylaromatic hydrocarbon which comprises passing to. an alkylation zone containing a boron trifluoride modified substantially anhydrous zirconium oxide, alkylatable aromatic hydrocarbon, olefinacting compound, and not more than 2.5 grams of boron tritiuoride per gram mol of olefin-acting compound, re acting therein said alkylatable aromatic hydrocarbon With said olefin-acting compound at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride modified substantially anhydrous zirconium oxide, and recovering therefrom alkylated aromatic hydrocarbon.

Another embodiment of this invention relates to a process for the production of an alkylbenzene hydrocarbon which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, alkylatable benzene hydrocarbon, olefin, and not more than 2.5 grams of boron trifiuoride per gram mol of olefin, reacting therein said alkylatable benzene hydrocarbon with said olefin at alkylation cOnditiOns in the presence of an alkylation catalyst comprising said boron trifiuoride modified substantially anhydrous zirconia, and recovering therefrom alkylated benzene hydrocarbon.

A specific embodiment of this invention relates to a process for the production of ethylbenzene which comprises passing to an alkylation zone containing boron trifluoride modified substantially anhydrous zirconia, benzene, ethylene, and from about 0.001 grams to about 2.5 grams of boron trifiuoride per gram mol of ethylene, reacting therein said benzene With said ethylene at alkylation conditions including a temperature of from about 0 to about 300 C. and a pressure of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified substantially anhydrous zirconia. and recovering therefrom ethylbenzene.

A still further specific embodiment of this invention re- .lates to a process for the production of cumene which comprises passing to an alkylation zone containing boron tlrifluoride modified substantially anhydrous zirconia, benzene, propylene, and from about 0.001 grams to about 2.5 grams of boron trifiuoride per gram mol of propylene, reacting therein said benzene with said propylene at alkylation conditions including a temperature of from about 0 to about 300 C. and a pressure of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified substantially anhydrous zirconia, and recovering therefrom cumene.

We have found, when utilizing a catalyst comprising a boron trifiuoride modified substantially anhydrous zirconium oxide, that the alkylation of aromatic hydrocarbons with olefin-acting compounds is surprisingly easy when boron tn'fluoride is supplied in a quantity not greater than'2.5 grams of boron trifluoride per gram mol' of' olefin-acting compound. The quantity of boron trifluoride utilized may be appreciably less than 2.5 grams per gram mol of olefin-acting compound and conversion of the olefin-acting compound to alkylaromatic hydrocarbon still conversion of the olefin-acting compound is obtained to produce desired alkylaromatic hydrocarbons, even when the olefin-acting compound is present as a so-called diluent in a gas stream the other components of which are inert under the reaction conditions and which other components decrease the Partial pressure of the olefin present in the alkylation reaction zone. Furthermore, we have found that the use of a boron trifiuoride modified substantially anhydrous zirconium oxide along with the limited quantities of boron trifiuoride hereinabove described results in the attainment of completenes of reaction which has not been possible prior tothis time. Furthermore, when the boron trifiuoride modified substantially anhydrous zirconia is present in the alkylation reaction zone, it has been found that the boron trifiuoride may be added continuously, intermittently, or in some cases addition may be stopped, provided, of course, that the boron trifiuoride added was never greater than 2.5 grams per gram mol of olefin-acting compound. Thus, the process may be started with boron trifiuoride addition, for example, within the above set forth ranges, and the boron trifiuoride addition discontinued. Depending upon whether or not the boron trifiuoride modified substantially anhydrous zirconia retains its activity, it may or may not be necessary to add further quantities of boron trifiuoride within the above set forth ranges. This feature of the process of the present invention will be set forth more fully hereinafter.

Boron trifiuoride is a gas (B.P. ll C., M.P. l26 C.) which is readily soluble in most organic solvents. It may be utilized per se by merely bubbling into a reaction mixture or it may be utilized as a solution of the gas in an organic solvent such as the aromatic hydrocarbon to be alkylated, for example, benzene. Such solutions are within the generally broad scope of the use of a boron trifiuoride catalyst in the process of the present invention although not necessarily with equivalent results. Gaseous boron trifiuoride is preferred.

The preferred catalyst composition, a stated hereinabove, comprises boron trifiuoride and boron trifiuoride modified substantially anhydrous but not completely dry zirconia. By the use of the description substantially anhydrous but not completely dry zirconia, we mean zirconium dioxide which, on a dry basis, contains from about 0.1 to about 10% water, either physically or chemically combined with the zirconia. These amounts of water are determined as volatile matter lost from crystalline zirconia upon heating at 900 C. for extended periods of time, say one to fifty hours or more. In contrast to aluminas, substantially anhydrous but not completely dry zirconias appear to occur only in one crystalline modification when examined by X-ray diffraction techniques, even though the amount of combined water varies therein. The exact reason for the specific utility of crystalline zirconia in the process of this invention is not fully understood but it is believed to be connected with the number of residual hydroxyl groups on the surface of the zirconia. Modification of zirconia with boron trifiuoride may be carried out prior to the addition of the zirconia to the alkylation reaction zone or this modification may be carried out in. situ. Furthermore, this modification of the zirconia with boron trifiuoride may be carried out prior to contact of the boron trifiuoride modified zirconia with the aromatic hydrocarbon to be alkylated and the olefin-acting compound, or the modification may be carried out in the presence of the aromatic hydrocarbon to be alkylated, or in the presence of both the aromatic hydrocarbon to be alkylated and the olefinacting compound. Obviously there is some limitation upon this last mentioned method of zirconia modification. The modification of the above mentioned zirconia with boron trifiuoride is an exothermic reaction and care must be taken to provide for proper removal of the resultant heat. The modification of the zirconia is carried out by contacting the zirconia with from about 2% to about 100% by weight boron trifiuoride based on the zirconia.

4 In one manner of operation, the zirconia is placed as a fixed bed in a reaction zone, which may be the alkylation reaction zone, and the desired quantity of boron trifiuoride is: passed therethrough. In such a case, the boron trifiuoride may be utilized in so-called massive amounts or may be used in dilute form diluted with various other gases such as hydrogen, nitrogen, helium, etc. This contacting is normally carried out at room temperature although temperatures up to that to be utilized for the alkylation reaction, that is, temperatures up to about 300 C. may be used. With the preselected zirconia at room temperature, utilizing boron trifiuoride alone, a temperature wave will travel through the zirconia bed during this modification of the zirconia with boron trifiuoride,'

increasing the temperature of the zirconia from room temperature up to about 75 C. or more. As the boron trifiuoride content of the gases to be passed over the zirconia is diminished, this temperature increase also diminishes and can be controlled more readily in such instances. In another method for the modification of the above mentioned zirconia with boron trifiuoride, the zirconia may be placed as a fixed bed in the alkylation reaction zone, the boron trifiuoride dissolved in the aromatic hydrocarbon to be alkylated, and the solution of aromatic hydrocarbon and boron trifiuoride passed over the zirconia at the desired temperature until sufficient boron trifiuoride has modified the zirconia. When the gas phase treatment of the zirconia is carried out, it is noted that no boron trifiuoride passes through the zirconia bed until all of the zirconia has been modified by the boron trifiuoride. This same phenomena is observed during the modification of the zirconia with the aromatic hydrocarbon solutions containing boron trifiuoride. In another method, the

-modification of the zirconia can be accomplished by utilization of a mix-ture of aromatic hydrocarbon to be alkylated, olefin-acting compound, and boron trifiuoride which upon passage over the zirconia forms the desired boron trifiuoride modified zirconia in situ. In the latter case, of course, the activity of the system is low initially and increases as the complete modification of the zirconia with the boron trifiuoride takes place. The exact manner by which the boron trifiuoride modifies the zirconia is not understood. It may be that the modification is a result of complexing of the boron trifiuoride with the zirconia, or on the other hand, it may be that the boron trifiuoride reacts with residual hydroxyl groups On the zirconia surface. It has been found at any particular preselected temperature for treatment of substantially anhydrous zirconia, that the fluorine content of the treated zirconia attains a maximum which is not increased by further passage of boron trifiuoride over the same. This maximum fluorine or boron trifiuoride content of the zirconia increases with temperature and depends upon the specific zirconia selected. As stated hereinabove, the zirconia treatment is, in the preferred embodiment, carried out at a temperature equal to or just greater than the selected reaction temperature so that the zirconia will not necessarily tend to be modified further by the boron trifiuoride which may be added in amounts not more than 2.5 grams per gram mol of olefin-acting compound during the process and so that control of the aromatic hydrocarbon alkylation reaction is attained more readily. In any case, the zirconia resulting from any of the above mentioned boron trifiuoride treatments is referred .to herein in the specification and claims as boron trifiuoride modified substantially anhydrous zirconia.

This boron trifiuoride modified zirconia is utilized, as set forth hereinabove, along with not more than 2.5 grams of boron trifiuoride per gram mol of olefin acting compound. When the quantity of boron trifiuoride modified zirconia, along with boron trifiuoride, i that needed for catalysis of the herein described reaction, the reaction takes place readily. When the desired reaction has been completed, the recovered boron trifiuoride modified zirconia is free flowing and changed, if at all, solely from its original white appearance to a very light yellow or tan color. Of course, the zirconia contains quantities of boron and fluorine by analysis corresponding to that which will complex or react with the zirconia in the manner described hereinabove under the temperature conditions utilized for the reaction.

As set forth hereinabove, the present invention relates to a process for the alkylation of an alkylatable aromatic hydrocarbon with an olefin-acting compound in the presence of a catalyst comprising a boron trifiuoride modified substantially anhydrous zirconium oxide, and particularly in the presence of a catalyst comprising not more than 2.5 grams of boron trifiuoride per gram mol of olefin-acting compound and a boron trifluoride modified substantially anhydrous zirconia. Many aromatic hydrocarbons are utilizable as starting materials in the process of this invention. Preferred aromatic hydrocarbons are monocyclic aromatic hydrocarbons, that is, benzene hydrocarbons. Suitable aromatic hydrocarbons, which may be used alone or in admixture one with another, include benzene, toluene, ortho-xylene, meta-xylene, para-xylene, ethylbenzene, ortho-ethyltoluene, meta-ethyltoluene, paraethyltoluene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trirnethy1benzene or mesitylene, normalpropylbenzene, isopropylbenzene, etc. Higher molecular weight alkylaromatic hydrocarbons are also suitable as starting materials and include aromatic hydrocarbons such as are produced by the alkylation of aromatic hydrocarbons with olefin polymers. Such products are frequently referred to in the art as alkylate, and include hexylbenzene, nonylbenzene, dodecylbenzene, pentadecylbenzene, hexyltoluene, nonyltoluene, dodecyltoluene, pentadecyltoluene, etc. Very often alkylate is obtained as a high boiling fraction in which the alkyl group attached to the aromatic nucleus varies in size from about C to about C Other suitable alkylatable aromatic hydrocarbons include those with two or more aryl groups such as diphenyl, diphenylmethane, triphenyl, triphenylmethane, fluorene, stilbene, etc. Examples of other alkylatable aromatic hydrocarbons within the scope of this invention as starting materials containing condensed benzene rings include naphthalene, alpha-methylnaphthalene, beta-methylnaphthalene, anthracene, phenanthrene, napthacene, rubrene, etc. Furthermore, certain petroleum derived aromatic hydrocarbon containing gasoline, naphtha, etc. fractions also may be utilized. Of the above alkylatable aromatic hydrocarbons for use as starting materials in the process of this invention, the benzene hydrocarbons are preferred, and of the preferred benzene hydrocarbons, benzene itself is particularly preferred.

Suitable olefin-acting compounds or alkylating agents which may be charged in the process of this invention include monoolefins, diolefins, polyolefins, acetylenic hydrocarbons, and also alkyl chlorides, alkyl bromides, and alkyl iodides. The preferred olefin-acting compounds are olefinic hydrocarbons which comprise monoolefins having one double bond per molecule and polyolefins which have more than one double bond per molecule. Monoolefins which may be utilized as olefin-acting compounds or alkylating agents for alkylating alkylatable aromatic hydrocarbons in the presence of the hereinabove described catalyst are either normally gaseous or normally liquid and include ethylene, propylene, l-butene, Z-butene, isobutylene, annd higher normally liquid olefins such as pentenes, hexenes, heptenes, octenes, and higher molecular weight liquid olefins, the latter including various olefin polymers having from about 6 to about 18 carbon atoms per molecule such as propylene trimer, propylene tetramer, propylene pentamer, isobutylene dimer, isobutylene trimer, isobutylene tetramer, etc. Cycloolefins such as cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, may be utilized, but generally not under the same conditions of operation applying to non-cyclic olefins. The polyolefinic hydrocarbons utilizable in the process of this invention include conjugated diolefins such as butadiene and isoprene, as well as non-conjugated diolefins and other polyolefinic hydrocarbons, containing two or more double bonds per molecule. Acetylene and homologs thereof are also useful olefin-acting compounds.

As stated hereinabove, alkylation of the above alkylatable aromatic hydrocarbons may also be effected in the presence of the hereinabove referred to catalyst by reacting aromatic hydrocarbons with certain substances capable of producing olefinic hydrocarbons, or intermediates thereof, under the conditions of operation chosen for the process. Typical olefin producing substances capable of use include alkyl chlorides, alkyl bromides, and alkyl iodides capable of undergoing dehydrohalogenation to form olefinic hydrocarbons and thus containing at least two carbon atoms per molecule. Examples of such alkyl halides include ethyl chloride, normal propyl chloride, isopropyl chloride, normal butyl chloride, isobutyl chloride, secondary butyl chloride, tertiary butyl chloride, amyl chlorides, hexyl chlorides, etc., ethyl bromide, normal propyl bromide, isopropyl bromide, normal butyl bromide, isobutyl bromide, secondary butyl bromide, tertiary butyl bromide, amyl bromides, hexyl bromides, etc., ethyl iodide, normal propyl iodide, etc.

As stated hereinabove, olefin hydrocarbons, especially normally gaseous olefin hydrocarbons, are particularly preferred olefin-acting compounds or alkylating agents for use in the process of the present invention. As stated. the process can be successfully applied to and utilized for conversion of olefin hydrocarbons when these olefin hydrocarbons are present in minor quantities in gas streams. Thus, in contrast to prior art processes, the normally gaseous olefin hydrocarbon for use in the process of the present invention, need not be purified or concentrated. Such normally gaseous olefin hydrocarbons appear in minor concentrations in various refinery gas streams, usually diluted with various unreactive gases such as hydrogen, nitrogen, methane, ethane, propane, etc. These gas streams containing minor quantities of olefin hydrocarbon are obtained in petroleum refineries from various refinery installations including thermal cracking units, catalytic cracking units, thermal reforming units, coking units, polymerization units, etc. Such refinery gas streams have in the past often been burned for fuel value since an economical process for their utilization as alkylating agents or olefin-acting compounds has not been available except where concentration of the olefin hydrocarbons has been carried out concurrently therewith. This is particularly ture for refinery gas streams containing relatively minor quantities of olefin hydrocarbons such as ethylene. Thus, it has been possible catalytically to polymerize propylene and/ or various butenes in refinery gas streams but the off-gases from such processes still contain ethylene. Prior to our invention it has been necessary to purify and concentrate this ethylene or to use it for fuel. These refinery gas streamscontaining minor quantities of olefin hydrocarbons are known as off-gases. In addition to containing minor quantities of olefin hydrocarbons such as ethylene, propylene, and the various butenes, depending upon their source, they contain varying quantities of nitrogen, hydrogen, and various normally gaseous paraflinic hydrocarbons. Thus, a refinery off-gas ethylene stream may contain varying quantities of hydrogen, nitrogen, methane, and ethane with the ethylene in minor proportion, while a refinery off-gas propylene stream is normally diluted with propane and contains the propylene in minor quantities, and a refinery off-gas butene stream is normally diluted with butanes and contains the butenes in minor quantities. A typical analysis in mol percent for a utilizable refinery off-gas from a catalytic cracking unit is as follows: nitrogen, 4.0%; carbon monoxide, 0.2%; hydrogen, 5.4%; methane, 37.8%; ethylene, 10.3%; ethane, 24.7%; propylene, 6.4%; propane, 10.7%; and C hydrocarbons, 0.5%. It

is readily observed that the total olefin content of this gas stream is 16.7 mol percent and the ethylene content is even lower, namely 10.3 mol percent. Such gas streams containing olefin hydrocarbons in minor or dilute quantities are particularly preferred alkylating agents or olefinacting compounds within the broad scope of the present invention. It is readily apparent that only the olefin content of such gas streams undergoes reaction in the process of this invention, and that the remaining gases free from olefin hydrocarbons are vented from the process.

In accordance with the process of the present invention, the alkylation of alkylatable aromatic hydrocarbons with olefin-acting compounds reaction to produce alkylated aromatic hydrocarbons of higher molecular weight than those charged to the process is effected in the presence of the above indicated catalyst at a temperature of from about 0 C., or lower to about 300 C. or higher, and preferably from about 20 to about 250 C., although the exact temperature needed for a particular aromatic hydrocarbon alkylation reaction will depend upon the alkylat able aromatic hydrocarbon and olefin-acting compound employed. The alkylation reaction is usually carried out at a pressure of from about substantially atmospheric to about 200 atmospheres. The pressure utilized is usually selected to maintain the alkylatable aromatic hydrocarbon in substantially liquid phase. Within the above temperature and pressure ranges, it is not always possible to maintain the olefin-acting compound in liquid phase. Thus, when utilizing a refinery olf-gas containing minor quantities of ethylene, the ethylene will be dissolved in the liquid phase alkylatable aromatic hydrocarbon to the extent governed by temperature, pressure, and solubility considerations. However, a portion thereof undoubtedly will be in the gas phase. When possible, it is preferred to maintain all of the reactants in liquid phase. Such is not always possible, however as set forth hereinabove. Referring to the aromatic hydrocarbon subjected to alkylation, it is preferable to have present from 2 to or more, sometimes up to 20, molecular proportions of alkylatable aromatic hydrocarbon per one molecular proportion of olefin-acting compound introduced therewith to the alkylation zone. The higher molecular ratios of alkylatable aromatic hydrocarbon to olefin are particularly necessary when the olefin employed in the alkylation process is a high molecular weigh-t olefin boiling generally higher than pentenes, since these olefins frequently undergo depolymerization prior to or substantially simultaneously with alkylation so that one molecular proportion of such an olefin can thus alkylate two or more molecular proportions of the alkylatable aromatic hydrocarbon. The higher molecular ratios of alkylatable aromatic hydrocarbon to olefin also tend to reduce the formation of polyalkylated products because of the operation of the law of mass action under these conditions.

In converting aromatic hydrocarbons to efiect alkylation thereof with the type of catalysts herein described, either batch or continuous operations may be employed. The actual operation of the process admits of some modification depending upon the normal phase of the reacting constituents, whether the catalyst utilized is not more than 2.5 grams of boron trifiuoride per gram mol of olefin-acting compound along with a boron trifluoride modified zirconia, or said boron trifiuoride modified zirconia alone, and whether batch or continuous operations are employed. In one type of batch operation, an aromatic hydrocarbon to be alkylated, for example benzene, is brought to a temperature and pressure within the approximate range specified in the presence of a catalyst comprising boron trifluoride and boron trifluoride modified substantially anhydrous zirconia having a concentration corresponding to a suificiently high activity and alkylation of the benzene is efi'ected by the gradual introduction under pressure of an olefin such as ethylene, in a manner to attain contact of the catalyst and reactants and in a quantity so that the amount of boron trifiuoride utilized is from about 0.001 gram to about 2.5 grams 8 per gram mol of olefin. After a sulficient time at the desired'temperature and pressure, the gases, if any, are vented and the alkylated aromatic hydrocarbon separated from the reaction products.

In another manner of operation, the aromatic hydrocarbon may be mixed with the olefin at a suitable temperature in the presence of suflicient boron trifluoride modified zirconia, and boron trifiuoride is then added to attain an amount between from about 0.001 gram to about 2.5 grams per gram mol of olefin. Then, reaction is induced by sufiiciently long contact time with the catalyst. Alltylation may be allowed to progress to different stages depending upon contact time. In the case of the alkylation of benzene with normally gaseous olefins, the most desirable product is that obtained by the utilization in the process of molar quantities of benzene exceeding those of the olefin. In a batch type of operation, the amount of boron trifluoride modified zirconia utilized will range from about 1% to about 50% by weight based on the aromatic hydrocarbon. With this quantity of boron trifiuoride modified zirconia, and boron trifiuoride as set forth hereinabove, the contact time may be varied from about 0.1 to about 25 hours or more. Contact time is not only dependent upon the quantity of catalyst utilized but also upon the efficiency of mixing, shorter contact times being attained by increasing mixing. After batch treatment, the boron trifinoride component of the catalyst is removed in any suitable manner, such as by venting or caustic washing, the organic layer or fraction is decanted or filtered from the boron trifiuoride modified zirconia, and the organic product or fraction is then subjected to separation such as by fractionation for the recovery of the desired reaction product or products.

In one type of continuous operation, a liquid aromatic hydrocarbon, such as benzene, containing dissolved therein the requisite amount of boron trifluoride, may be pumped through a reactor containing a bed of solid boron trifiuoride modified zirconia. The olefin-acting compound may be added to the aromatic hydrocarbon stream prior to contact of this stream with the solid zirconia bed, or it may be introduced at various points in the zirconia bed, and it may be introduced continuously or intermittently, as set forth above. In this type of an operation, the hourly liquid space velocity of the aromatic hydrocarbon reactant will vary from about 0.25 to about 20 or more. The details of continuous processes of this general character are familiar to those skilled in the art of alkylation of aromatic hydrocarbons and any necessary additions or modifications of the above general procedures will be more or less obvious and can be made without departing from the broad scope of this invention.

The process of the present invention is illustrated by the following examples which are introduced for the purpose of illustration and with no intention of unduly limiting the generally broad scope of this invention.

EXAMPLE I This example illustrates the fact that boron trifiuoride alone, in the quantities herein disclosed, is not a catalyst for the alkylation of benzene with ethylene. The experiment carried out for this example was performed in an 850 milliliter knife edge closure rotatable high pressure autoclave. To this autoclave was added 270 milliliters (236 grams or 3 mols) of benzene, after which the autoclave was closed. Next, 2.1 grams of boron trifluoride was pressured into the autoclave. Then sufiicient ethylene was added so that the pressure attained in the autoclave was 27 atmospheres. This amount of ethylene is approximately 1 molecular weight thereof, and in this particular case equaled 31.2 grams of ethylene. Thus, the grams of BF per gram mol of ethylene used was 2.1. The autoclave was then heated to C., and heated and rotated at this temperature for 3 hours time.

At the expiration of this time, the autoclave was cooled and the pressure remaining thereon was released. After removal of the boron trifluoride and unreacted ethylene,

the liquid product was analyzed by infra-red diffraction techniques. The results of this analysis showed that the product contained 99.7 weight percent benzene and 0.3 weight percent ethylbenzene. This amount of ethylbenzene is equivalent to 0.7 gram. It is obvious from the above experiment that this amount of boron trifiuoride alone is not a satisfactory catalyst for this reaction.

EXAMPLE II This example was carried out utilizing as the catalyst therefor a boron trifiuoride modified substantially anhydrous zirconium dioxide, along with added boron trifiuoride. The zirconium dioxide was prepared by dissolving zirconium carbonate in nitric acid after which zirconium hydroxide was precipitated therefrom by the addition thereto of ammonium hydroxide. The zirconium hydroxide was filtered from the solution, washed with water and dried. After drying, when the zirconium hydroxide had become powdery, it was calcined at 650 C. for hours time. X-ray diffraction examination of this zirconia indicated that it consisted of zirconia only in its one crystalline form, namely, monoclinic. The zirconia had a surface area of 82 square meters per gram, a pore volume of 0.080 cubic centimeters per gram, and a pore diameter of 39 Angstrom units. It still contained about 3.20% volatile matter (presumably water) which is the weight loss experienced upon heating the zirconia at 900 C.

A portion of the above zirconia was treated with boron trifiuoride at 150 C. until boron trifiuoride was observed in the eflluent gases therefrom. After boron trifiuoride modification, it contained 1.0% boron and 1.9% by weight of fluorine. It had an apparent bulk density of 1.925 grams per milliliter and its color was a light gray-white.

This boron trifiuoride modified substantially anhydrous zirconia, in the quantity of 100 milliliters, was placed in the rotating autoclave described in Example I. Next, 270 milliliters of dry benzene was added and the autoclave closed. Then, 2.0 grams of boron trifiuoride was pressured into the autoclave, after which the autoclave was pressured to 27 atmospheres with ethylene. The quantity of ethylene utilized here was 28 grams so that the ratio of BF in grams to the gram-mols of ethylene was 2.0. Here again, the autoclave was heated and rotated at 150 C. for 3 hours time.

After cooling, removal of boron trifiuoride and any unreacted ethylene from the liquid effiuent, the liquid product was analyzed by infra-red techniques. It was found to contain 64.9 weight percent benzene, 30.3 weight percent ethylbenzene, and 4.8 weight percent diethylbenzenes. These quantities are equivalent to the production of 79.4 grams of ethylbenzene and 12.6 grams of diethylbenzenes. These quantities of ethylbenzene and diethylbenzenes indicate substantially complete conversion of the ethylene to alkylated benzene hydrocarbons under the above conditions, in the presence of boron trifluoride modified substantially anhydrous zirconia and the indicated quantity of added boron trifiuoride.

EXAMPLE HI This example was carried out to illustrate the fact that still smaller quantities of boron trifiuoridemay be utilized along with a boron trifiuoride modified substantially an hydrous zirconia, and that substantially complete conversion of ethylene to alkylated benzene hydrocarbons results therefrom. In this example, another sample of substantially anhydrous zirconia, prepared in the manner set forth in Example II, was utilized. X-ray difiraction analysis of this zirconia indicated monoclinic crystalline form. This particular zirconia had a surface area of 80 square meters per gram, a pore volume of 0.078 cubic centimeters per gram, and a pore diameter of 39 angstrom units. It gave off 5.85% volatile matter at 900 C., which is considered to be equivalent to its water content.

A portion of the above zirconia was treated at about 150 C. with boron trifiuoride until'borontrifluoride was observed in the exit gases therefrom. The boron trifluoride modified substantially anhydrous zirconia was found to contain, on analysis, 1.4 weight percent boron and 2.0 weight percent fluorine. Its surface properties after modification were a surface area of 48 square meters per gram, a pore volume of 0.058 cubic centimeters per gram, and a pore diameter of 48 angstrom units. At this point it had an apparent bulk density of 1.86 and was a pale tan color.

To the same autoclave described in Example I, there was added milliliters of this boron trifiuoride modified substantially anhydrous zirconia. Next, 270 milliliters of benzene was added to the autoclave following which the autoclave was closed. Then, 0.19 grams of boron trifiuoride was pressured into the autoclave following which the autoclave was pressured to 27 atmospheres with ethylene. Since this amount of ethylene is approximately 1 molecular Weight thereof, the number of grams of boron trifiuoride per gram mol of ethylene was 0.19. Here again, the autoclave was rotated and heated at C. for 3 hours time.

After cooling, and removal of boron trifiuoride and unreacted ethylene, if any, the liquid product was analyzed by infra-red techniques. It was found to contain 64.7 weight percent benzene, 30.9 weight percent ethylbenzene, and 4.4 weight percent diethylbenzenes. This is equivalent to the production of 81.0 grams of ethylbenzene and 11.5 grams of diethylbenzenes. These quantities of ethylbenzene and diethylbenzenes are equivalent to substantially complete conversion of the ethylene to alkylated benzene hydrocarbons at the conditions utilized in the presence of a boron trifiuoride modified substantially anhydrous zirconia along with added boron trifiuoride.

We claim as our invention:

1. A process for the production of an alkylaromatic hydrocarbon Which comprises passing to an alkylation zone containing boron trfiuoride modified substantially anhydrous zirconia, alkylatable aromatic hydrocarbon, olefin-acting compound, and not more than 2.5 grams of boron trifiuoride per gram mol of olefin-acting compound, reacting therein said alkylatable aromatic hydrocarbon with said olefin-acting compound at alkylation conditions in the presence of said boron trifiuoride and said boron trifiuoride modified zirconia, and recovering therefrom alkylated aromatic hydrocarbon.

2. A process for the production of an alkylaromatic hydrocarbon which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, alkylatable aromatic hydrocarbon, unsaturated hydrocarbon, and not more than 2.5 grams of boron trifiuoride per gram mol of unsaturated hydrocarbon, reacting therein said alkylatable aromatic hydrocarbon with said unsaturated hydrocarbon at alkylation conditions in the presence of said boron trifiuoride and said boron trifiuoride modified zirconia, and recovering therefrom alkylated aromatic hydrocarbon.

3. A process for the production of an alkylaromatic hydrocarbon which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, alkylatable aromatic hydrocarbon, olefin, and from about 0.001 grams to about 2.5 grams of boron trifiuoride per gram mol of olefin, reacting therein said alkylatable aromatic hydrocarbon with said olefin at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified zirconia, and recovering therefrom alkylated aromatic hydrocarbon.

4. A process for the production of an alkylbenzene hydrocarbon which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, alkylatable benzene hydrocarbon, olefin, and from about 0.001 grams to about 2.5 grams of boron trifiuoride per gram mol of olefin, reacting therein said alkylatable benzene hydrocarbon with said olefin at alkylation conditions in the presence of an alkylation catalist comprising said boron trifiuoride and boron trifluoride modified zirconia, and recovering therefrom alkylated benzene hydrocarbon.

5. A process for the production of ethylbenzene which comprises passing to an alkylation zone containing boron trifluoride modified substantially anhydrous zirconia, benzene, ethylene, and from about 0.001 grams to about 2.5 grams of boron trifluoride per gram mol of ethylene, reacting therein said benzene with said ethylene at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified zirconia, and recovering therefrom ethylbenzene.

6. A process for the production of cumene which comprises passing to an alkylation zone containing boron trifluoride modified substantially anhydrous Zirconia, benzene, propylene, and from about 0.001 grams to about 2.5 grams of boron trifluoride per gram mol of propylene, reacting therein said benzene with said propylene at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifiuoride modified zirconia, and recovering therefrom cumene.

7. A process for the production of butylbenzene which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, benzene, a butene, and from about 0.001 grams to about 2.5 grams of boron trifluoride per gram mol of butene, reacting therein said benzene with said butene at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified zirconia, and recovering therefrom butylbenzene.

8. A process for the production oi ethylbenzene which comprises passing to an alkylation zone containing boron trifluoride modified substantially anhydrous zirconia, benzene, ethylene, and from about 0.001 grams to about 2.5 grams of boron trifiuoride per gram mol of ethylene, reacting therein said benzene with said ethylene at alkylation conditions including a temperature of from about 12 to about'300 C. and a pressure of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifluoride and boron triiluoride modified zirconia, and recovering therefrom ethylbenzene.

9. A process for the production of cumene which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, benzene, propylene, and from about 0.001 gram to about 2.5 grams of boron trifiuoride per gram mol of propylene, reacting therein said benzene with said propylene at alkylation conditions including a temperature of from about 0 to about 300 C. and a pressure of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifiuoride modified zirconia, and recovering therefrom cumene.

10. A process for the production of butylbenzene which comprises passing to an alkylation zone containing boron trifiuoride modified substantially anhydrous zirconia, benzene, a butene, and from about 0.001 gram to about 2.5 grams of boron trifiuoride per gram mol of butene, reacting therein said benzene with said butene at alkylation conditions including a temperature of from about 0 to about 300 C. and a pressure of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified zirconia, and recovering therefrom butylbenzenet References Cited in the file of this patent UNITED STATES PATENTS 2,380,234 Hall July 10, 1945 2,804,491 May Aug. 27, 1957 2,955,143 Bloch Oct. 4, 1960 FOREIGN PATENTS 1,028,700 France May 27, 1953 

1. A PROCESS FOR THE PRODUCTION OF AN ALKYLAROMATIC HYDROCARBON WHICH COMPRISES PASSING TO AN ALKYLATION ZONE CONTAINING BORON TRIFLUORIDE MODIFIED SUBSTANTIALLY ANHYDROUS ZIRCONIA, ALKYLATABLE AROMATIC HYDROCARBON, OLEFIN-ACTING COMPOUND, AND NOT MORE THAN 2.5 GRAMS OF BORON TRIFLUORIDE PER GRAM MOL OF OLEFIN-ACTING COMPOUND, REACTING THEREIN SAID ALKYLATABLE AROMATIC HYDROCARBON WITH SAID OLEFIN-ACTING COMPOUND AT ALKYLATION CONDITIONS IN THE PRESENCE OF SAID BORON TRIFLUORIDE AND SAID BORON TRIFLUORIDE MODIFIED ZIRCONIA, AND RECOVERING THEREFROM ALKYLATED AROMATIC HYDROCARBON. 